Print message to Info in Blender 2.8
For all the lazy people, who don't like reading the API on how to register and call an operator:

import bpy

class RENDER_OT_test(bpy.types.Operator):
    """Tooltip"""
    bl_idname = "render.custom_test"
    bl_label = "Test"

    def execute(self, context):
        self.report({'INFO'}, 'Printing report to Info window.')
        return {'FINISHED'}

def register():
    bpy.utils.register_class(RENDER_OT_test)

def unregister():
    bpy.utils.unregister_class(RENDER_OT_test)

if __name__ == "__main__":
    register()


Run the script, press F3 to open up the search menu, type Testand press Enter.

No additional link to prevent lazy people from getting even more lazy.